Electric pump



March 23, 1965 v. D. ROOSA 3,174,433

ELECTRIC PUMP Filed July 16, 1963 2 Sheets-Sheet l 65/6 70 72 73 3 FIG. 2 62 a 57 5% H6. 5 af/ 70 /0\ Z5 INVENTOR. 39 /9 20 VERNON D. ROQSA ATTORNEYS ELECTRIC PUMP March 23 1965 2 Sheets s eet 2 Filed July 1965 f I QM Q Q l VERN ON D. ROOSA ATTORNEYS United States Patent 3,174,433 ELECTRIC PUMP Vernon D. Roosa, West Hartford, Conn. Hartford l lachiiie Screw Company, P.0. Box 1440, Hartford, onn.

Filed July 16, 1963, Ser. No. 297,172 11 Claims. (Cl. 103-53) This application is a continuation-in-part of applicants earlier filed copending application Serial Number 140,096, filed September 22, 1961, now abandoned.

This invention relates to electromagnetically actuated pumps particularly suited for use as liquid fuel supply pumps for internal combustion engines and has for a primary object the provision of an unusually compact and durable pump capable of unattended operation.

A further object of this invention is the provision of an improved electromagnetically actuated pump having a minimum number of economically manufactured pants that can be easily assembled to product a reliable pump capable of delivering appreciable quantities of fluid.

A still further object of this invention is the provision of an improved pump of the type described suitable for in-line mounting in a fluid conduit without the use of accessory mounting devices.

An additional object of this invention is the provision of an improved magnetic pump suitable for use submersed in highly combustible liquids such as gasoline.

Other objects will be in part obvious and in part pointed out more in. detail hereinafter.

The invention according-1y consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawings:

FIG. 1 is an exploded perspective view of one embodiment of the invention;

FIG. 2 is a cross section View of the pump of FIG. 1 with the parts assembled;

FIG. 3 is a top plan view of the armature assembly;

FIG. 4 is a cross section view taken along the lines 44 of FIG. 3;

FIG. 5 is a cross section view similar to FIG. 2 showing the position of the armature assembly with the solenoid energized and with the pump being in-line mounted in a fluid conduit;

FIG. 6 is an exploded perspective view of another embodiment of the invention;

1 FIG. 7 is a cross section view of the pump of FIG. 6 with the parts assembled and showing the armature assembly during its movement with the solenoid energized; and

FIG. 8 is a cross section view similar to FIG. 7 showing the position of the armature assembly with the solenoid de-energized and as the armature is returning to its de-energized position.

Turning now to the drawings and particularly FIGS. 1 and 5, it is seen that one form of the pump of this invention comprises a generally cylindrical housing 10 in cluding a base 12 and a cap 14 in which are formed an inlet 15, an outlet 16 and which are secured together to enclose the operating parts of the pump. Asshown in FIG. 5 the inlet 15 is connected to a fluid supply conduit 13 and outlet 16 is connected to a fluid outlet conduit 17 whereby the pump is in-line mounted on the tubing of the fluid conduit which serves as its sole support.

The base 12 is made from a material having suitable magnetic properties and is generally cup-shaped to provide an outer peripheral wall 18 and a bottom wall "Ice 19. Integral with the bottom wall 19 in the embodiment of FIG. 2 there is provided a central post 29 whose upper end face 22 is substantially coplanar with the upper end face 23 of the peripheral wall 18 and which cooperates with peripheral wall 18 to define a generally annular chamber 25 in which is located a coil 26 that is potted in position with an insulating material 28 that substantially fills the free volume of the annular chamber 25. The inlet passageway 15 is defined by a bore 30 in post 20, which bore extends throughout the length of the post and is provided with internal threads 31 to establish connection to fluid supply conduit 13 in a conventional manner. Electrical connections are established to the coil 26 by stud 33 which is received in recess 34 in base bottom wall 19 to engage one of the end turns of the solenoid. Stud 33 also serves to secure terminal 36 to the housing but electrically insulated therefrom by insulating disc 37. In the illustrated embodiment, the second connection to the coil is established by grounding the other solenoid end turn to the hous' ing with conductor 39.

The armature assembly generally designated 42 comprises a rigid disc of magnetic material, or armature 44, dimensioned to overlie and engage the circular end face 23 of wall 18 and the end face 22 of post 20 to provide a low reluctance toroidal path for the flux produced by coil 26 when it is suitably energized. Armature assembly 42 also includes mounting and valve cage member 46 which is welded or otherwise attached to armature 44 and which is provided with a raised rim 48 and a groove 49 which define a circumferential shoulder 50 that tightly engages a flexible, imperforate skirt 52 formed of neoprene or the like. As most clearly seen in FIGS. 2 and 5, the outer periphery of skirt 52 is clamped between shoulder 54 of cap 14 and ring 55 when the de pending wall 57 of cap 14 is secured to the radially projectinglip 59' of base 12 so as to establish sealing en gagement between the housing members and throughout the full periphery of the skirt. The ring 55 can be formed of magnetic material to reduce the effective air gap between the base and the armature at the beginning of the movement of the armature 44 when coil 26 is energized thereby to reduce the power required to operate the pump as hereinafter explained. When pump power requirements are not critical, a nonmagnetic spacer ring cient axial length to permit reciprocating movement of armature 44 by flexing of skirt 52. In order to estab lish a remote or rest position of the armature assembly that is spaced from the base 12, there is provided a spring 70 whose lower end has a hook portion 71 that engages the legs 73 of the cage on mounting member 46. The other end of spring 70 is provided with a large diameter convolution 72 which rests upon the upper end 74 of stud 62. Spring 70 is constructed so that, with the armature assembly shown in the remote or rest position of FIG. 2, the spring is unstressed so as to reduce the power requirements of the solenoid necessary to effect movement of the armature assembly. It will be noted that the edges of armature 44 are slightly spaced from the inner periphery of the ring 55 to provide an annular clearance therebetween thereby to eliminate mechanical friction during operation of the pump. The armature 44 is, in effect, a

free floating assembly with the biasing forces of resilient.

skirt 52 and return spring 70 providing the only mechanical guiding force thereon during the operation of the pump.

The valving required to complete the pump of this invention is exceedingly simple in construction and location so as to further reduce the size and cost of the pump while improving its operating efiiciency. Two valves are required in this pump, one of which is generally designated 80 and is located in the bore 36 of base 12, i.e., the inlet passageway. The valve 80 is comprised of valve seat member 82 positioned in the passageway 34) and defining therewith a plurality of fluid passageways $3 therethrough. A nonmagnetic washer 85 is dimensioned so as to overlie the passageways and sealingly engage the seat 82 to close the passageways 83. Limited movement is accorded to the washer 85 by stud 87 which extends through the aperture in the washer and which is supported by the seat 82, stud 87 being provided with an enlarged head 88 to limit movement of the washer. For completeness it is noted at this point that armature 44 is provided with a recess 89 in its lower face to accommodate the head of stud 88 and washer 85. I

t The second valve, generally designated 90, is centrally located in the annular armature assembly so as to be coaxially aligned with the inlet and the outlet 16 and constitutes the sole fluid flow path past the armature. Valve 90 is comprised of a plurality of fluid flow passageways 91 formed in the armature 44, which paths are selectively closed by a nonmagnetic washer 93 which is dimensioned to overlie and sealingly engage the upper surface of the armature. The movement of this Washer or valve member is controlled and limited by the legs 73 of the member 46 which, in effect, define a cage that positions the washer laterally of the armature 44 and limits movement of the washer away from the armature.

Further understanding of my invention can be obtained from a description of the operation of the foregoing structure. With the coil 26 tie-energized, spring 70 positions the armature assembly 42 in the position shown in FIG. 2. Assuming that the coil has just been deenergized, the armature assembly 42 is completing its travel away from the base so that valve 90 is closed and valve is open withfluid flowing from the inlet through valve 89 and into the space between thearmature assembly 42 and the base 12. Upon energization of coil 26 the armature 44 moves towards the base 12 thereby creating a positive pressure on the outlet side 'of washer 85 to force it to the closed position. If ring 55 is formed of magnetic material, the flux may pass from the peripheral wall 18 of the base 12 through ring 55 and across the small annular air gap into the armature 44 to minimize the reluctance of the magnetic circuit thereby to reduce the power required. Upon closure of valve 80, a positive pressure is created on the inlet side of valve 99 thereby raising valve washer 93 to open valve 90 and permit fluid flow therethrough to the outlet side of the armature assembly, which condition is shown in FIG. 5. De-energization of the solenoid permits the armature assembly to return to the position shown in FIG. 2 thereby forcing fluid out of the outlet passageway and drawing more fluid into the space between the armature assembly and the base. Pulsed energization of the coil will provide the desired pumping action, the delivery rate being controlled by the pulse rate.

Referring now to FIGS. 6-8 in which like numerals refer to like parts shown in FIGS. 1-5, there is illustrated another embodiment of this invention. In this embodiment, annular armature 44 is shown as being formed of a single inflexible disc of magnetic material having an annular wedge-shaped groove 45 in the outer periphery thereof. The flexible imperforate skirt 52 of this embodiment is expanded over the edge of the armature for insertion in the wedge-shaped groove 45, and since it is formed of a resilient material, provides a seal with the walls of the wedge-shaped groove 45. As in the embodiment of FIGS. 1-5, the outer periphery of the skirt 52 is clamped between the shoulder 54 of the cap 14 and the spacer ring 55.

As best shown in FIG. 6, the port for armature 44 comprises a single annular hole centrally positioned in the armature 44 which is positioned coaxially with inlet 16 and outlet 15.

A plate valve a is secured to the inner end wall of the cap 14 by an upset stud 84 so that, in its relaxed position, plate valve 85a is biased to close inlet 16. As shown, a reinforcing spring 36 is provided to increase the biasing force holding plate valve 85a in a closed position. Plate valve 85a and reinforcing spring 86 may be formed of any suitable spring material such, for example, as tempered beryllium copper.

An important feature of this embodiment of the invention is the return spring 76a for biasing the armature 44 in a direction opposite to the magnetic force applied to the armature by coil 26. As best shown in FIG. 6, this spring comprises an annular spring member having a plurality of inwardly directed and upwardly curved fingers 70b for engaging the lower surface of the armature 44 to urge the armature away from the base 12 of the pump. One of the inwardly directed fingers is extended and enlarged to overlie central port 91a of the armature 44 to provide a one-way plate valve therefor. Annular return spring 70a may be formed of any suitable nonmagnetic spring material such as tempered beryllium copper.

The outer edge of annular return spring 7ta is posi tioned between the upper edge of peripheral wall 13 of the base 12 of the pump housing and a thin spacer ring 95 formed of a nonmagnetic resilient material such as polyethylene glycol terephthalate. The sandwich formed of the outer edge of return springitia andspacer ring 95 is clamped between the ends of peripheral wall 57 of cap 14 and peripheral wall 18 of base 12 to seal the base 12 to the cap 14. As shown, a knurled surface 58 is provided on the projecting lip 5? of the base 12 to nonrotatably secure the base 12 and the cap 14 when the edge of the cap is crimped therearoun'd.

It will be readily apparent that the operation of the modified form of the invention shown in FIGS. 6-8 is similar to that of the form of the invention shown in FIGS. 1-5. With the coil 26 de-energized, the annular return spring 70a biases the armature 44 upwardly as shown in FIGS. 7 and 8. Upon energizing coil 26, the magnetic flux, which is closed through armature 44, attracts armature 44 inwardly. In this regard, it will be noted that the peripheral edge of the armature 44 overlies spacer ring 95 which serves to prevent contact between the armature 44 and the annular spring 7 0a. Since the spacer ring 95 is resilient, it thus serves to cushion the impact forces applied by the armature tothe sprmg 70a thereby to prevent the peening or work hardening of the spring. Moreover, by providing a minimum space between the spring 76a and the armature 44, the full straightening, or reverse bending, of the fingers 76b of spring 70a is avoided so that the stress applied to these fingers is reduced thereby substantially lengthening their useful life. Since the spacer ring 95 is formed of a nonmagnetic material, it, together with the nonmagnetic return spring 70a, serves to provide a minimum air gap between the armature 44 and the wall 18 and the central post 20 of the base. Thus, when coil 26 is de-energized, any residual magnetism which may remain in the magnetic circuit opposing the biasing force of return spring 70a is minimized.

From the foregoing description of the structure and operation of my improved pump, it is apparent that a. minimum number of small, simple parts have been utilized to construct an effective electromagnetically actuated pump which, by virtue of its coaxial arrangement of its inlet, outlet and armature ports,. can be in-line mounted directly on the tubing of the fluid conduit so as to preclude the necessity for separate mounting accessories while at the same time occupying a minimum volume of space. Moreover, this coaxial arrangement results in concentrically balanced static and dynamic forces on the armature so that it is subjected essentially to simple rectilinear movement despite the floating mounting of the armature 44. Thus, the bending and torsional vibrations imposed on the fluid conduit in which the pump is mounted as well as the power requirements are minimized. Because of the absence of any circuit making and breaking elements Within the pump itself, its immer- Sion within the combustible fluid is safely permitted, the desired pulsing device being located in a remote position. Additionally, it is noted that this pump permits fluid flow from inlet to outlet even while inoperative thereby permitting its use on the inlet side of another pump without impairing the operation of that pump.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. An electromagnetically actuated pump comprising a housing having an inlet and an outlet coaxially aligned therewith, an enlarged fluid passageway between said inlet and said outlet, an armature formed of magnetic material positioned in the fluid passageway and spaced from the peripheral walls thereof to provide a peripheral clearance, port means in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the peripheral walls of the fluid passageway, a first one-way valve on said armature to pass fluid through said port means of said armature, a second valve in said housing arranged to pass fluid only in the same direction as said first valve, a solenoid in said housing disposed between said inlet and outlet adjacent said armature, and spring means mounting said armature for rectilinear movement along the axis of said inlet and outlet with the port means thereof in coaxial alignment with the inlet and outlet of the housing, said spring means biasing said armature away from said solenoid whereby pulsed energization of said solenoid causes movement of said armature assembly rectilinearly relative to the axis of said inlet and outlet to pump fluid from said inlet to said outlet.

2. An electromagnetically actuated pump comprising a housing having an inlet and an outlet coaxially aligned therewith, an enlarged fluid passageway between said inlet and said outlet, an inflexible armature formed of magnetic material floatingly positioned in the fluid passageway and spaced from the peripheral walls thereof to provide a peripheral clearance, port means in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the peripheral walls of the fluid passageway, a first one-way valve on said armature to pass fluid through said port means of said armature, a second valve in said housing arranged to pass fluid only in the same direction as said first valve, a solenoid in said housing disposed between said inlet and outlet adjacent said armature, and spring means mounting said armature for rectilinear movement along the axis of said inlet and outlet with the port means thereof in coaxial alignment with the inlet and outlet of the housing, said spring means biasing said armature away from said solenoid whereby pulsed energization of said solenoid causes movement of said armature assembly rectilinearly relative to the axis of said inlet and outlet to pump fluid from said inlet to said outlet.

3. An electromagnetically actuated pump comprising a housing having an inlet and an outlet coaxially aligned therewith, an enlarged fluid passageway between said inlet and said outlet, an inflexible armature formed of magnetic material floatingly positioned in the fluid passageway and spaced from the peripheral walls thereof to provide a peripheral clearance, port means in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the peripheral walls of the fluid passageway, said skirt biasing said armature so as to coaxially align said port means with the inlet and the outlet, a first one-way valve on said armature to pass fluid through said port means of said armature, a second valve in said housing arranged to pass fluid only in the same direction as said first valve, a solenoid in said housing disposed between said inlet and outlet adjacent said armature, and spring means mounting said armature for rectilinear movement along the axis of said inlet and outlet with the port means thereof in coaxial alignment with the inlet and outlet of the housing, said spring means biasing said armature away from said solenoid whereby pulsed energization of said solenoid causes movement of said armature assembly rectilinearly relative to the axis of said inlet and outlet to pump fluid from said inlet to said outlet.

4. An electromagnetically actuated pump comprising a housing having an inlet and an outlet coaxially aligned therewith, an enlarged fluid passageway between said inlet and said outlet, an inflexible annular armature formed of magnetic material floatingly positioned in the fluid passageway and spaced from the peripheral walls thereof to provide a peripheral clearance, port means in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the peripheral walls of the fluid passageway, said skirt biasing said armature so as to coaxially align said port means with the inlet and the outlet, at first one-way valve on said armature to pass fluid through said port means of said armature, a second valve in said housing arranged to pass fluid only in the same direction as said first valve, a solenoid in said housing disposed between said inlet and outlet adjacent said armature, and spring means pivotally mounting said armature in said fluid passageway and biasing said armature away from said solenoid whereby the armature is subjected to static and dynamic forces concentrically balanced relative to said port means when pulsed energization of the solenoid causes movement of the armature assembly along the axis of the inlet and the outlet to pump fluid.

5. An electromagnetically actuated pump comprising a housing having an inlet and an outlet coaxially aligned therewith, an enlarged fluid passageway between said inlet and said outlet, an inflexible annular armature formed of magnetic material floatingly positioned in the fluid passageway and spaced from the peripheral walls thereof to provide a peripheral clearance, port means in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the peripheral walls of the fluid passageway, said skirt biasing said armature so as to coaxially align said port means with the inlet and the outlet, a first one-way valve on said armature to pass fluid through said port means of said armature, a second valve in said housing arranged to pass fluid only in the same direction as said first valve, a solenoid in said housing disposed between said inlet and outlet adjacent said armature, and spring means pivotally mounting said armature in said fluid passageway and biasing said armature away from said solenoid whereby the armature is subjected to static and dynamic forces concentrically balanced relative to said port means when pulsed energization of the solenoid causes movement of the armature assembly along the axis of the inlet and the outlet to pump fluid, said flexible peripheral skirt and said spring providing the sole means for mechanically guiding the armature.

6. An electromagnetically actuated pump comprising a fluid supply conduit and a fuel discharge conduit, a housing having an inlet and an outlet coaxially aligned therewith, coupling means for connecting said inlet and said outlet respectively to said conduits, an enlarged fluid passageway between said inlet and said outlet, an inflexible annular armature formed of magnetic material floatingly positioned in the fluid passageway and spaced from the peripheral walls thereof to provide a peripheral clearance, port means in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the peripheral walls of the fluid passageway, said skirt biasing said armature so as to coaxially align said port means with the inlet and the outlet, a first one-way valve on said armature to pass fluid through said port means of said armature, a second valve in said housing arranged to pass fluid only in the same direction as said first valve, a solenoid in said housing disposed between said inlet and outlet adjacent said armature, and spring means pivotally mounting said armature in said fluid passageway and biasing said armature away from said solenoid whereby the armature is subjected to static and dynamic forces concentrically balanced relative to said port means when pulsed energization of the solenoid causes movement of the armature assembly along the axis of the inlet and the outlet to pump fluid, said coupling means providing the sole support for said pump.

7. An electromagnetically actuated pump comprising a housing having an inlet and an outlet coaxially aligned therewith, an enlarged fluid passageway between said inlet and said outlet, an armature formed of magnetic material positioned in said fluid passageway and spaced from the side walls thereof to provide a peripheral clearance, central port means in said armature coaxially disposed relative to said inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the side walls of the fluid passageway, a first valve in the housing arranged to pass fluid only from said inlet to said outlet, a solenoid in the housing disposed between the inlet and the outlet adjacent said armature, and disc spring means mounting said armature for rectilinear movement along the axis of said inlet and outlet with the port means of said armature in coaxial alignment with said inlet and outlet, said spring means having a plurality of inwardly directed fingers engaging said armature to bias the same away from said solenoid, one of said fingers providing a second valve overlying the port means of said armature to pass fluid only in the same direction as said first valve whereby pulsed energization of the solenoid causes movement of said armature assembly rectilinearly relative to the axis of said inlet and said outlet.

8. An electromagnetically actuated pump comprising a housing having an inlet and an outlet coaxially aligned therewith, an enlarged fluid passageway between said inlet and said outlet, an armature formed of magnetic material positioned in said fluid passageway and spaced from the side walls thereof to provide a peripheral clearance, central port means in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance and sealing the armature to the side walls of the fluid passageway, a first valve in the housing arranged to pass fluid only from said inlet to said outlet, a solenoid in the housing disposed between the inlet and the outlet adjacent said armature, a disc spring positioned between said solenoid and said armature, said disc spring having a plurality of inwardly and upwardly directed fingers engaging said armature for biasing the armature away from said solenoid, one of said fingers having a portion overlying the central port means of said armature to provide a second valve to pass fluid in the same direction as said first valve, and a spacer disposed between said armature and said spring means to prevent contact therebetween.

9. A pump as described in claim 8 wherein the spacer is formed of a nonmagnetic material.

10. A pump as described in claim 8 wherein said spacer is resilient.

11. An electromagnetically actuated pump comprising a cylindrical housing having a concentrically disposed inlet and a concentrically disposed outlet coaxially aligned therewith, an enlarged fluid chamber between said inlet and said outlet, an inflexible armature formed of magnetic material disposed in said passageway and spaced from the side walls thereof to provide a peripheral clearance, a central aperture in said armature coaxially disposed relative to the inlet and the outlet to accommodate fluid flow past said armature, a flexible imperforate skirt disposed in said peripheral clearance for sealing the armature to the side walls of said housing, said skirt exerting a biasing force on said armature to urge it to a coaxial position within the housing, a first disc valve overlying the inlet of the housing to pass fluid only from said inlet to said outlet, an annular solenoid in the housing disposed between the armature and said outlet to produce a toroidal flux linking said armature to said housing, a spring disc positioned between the solenoid and said armature, said spring disc having a plurality of inwardly and upwardly directed fingers engaging said armature to bias the armature away from said solenoid, one of said fingers providing an enlarged portion overlying the aperture of said armature to provide a second valve for passing fluid in the same direction as the first valve, and a resilient nonmagnetic spacer disposed between said armature and said disc spring to prevent contact therebetween.

References Cited by the Examiner UNITED STATES PATENTS 1,690,348 11/28 Wallace 103-53 1,888,322 11/32 Lanctot et al. 10353 2,630,760 3/53 Ryba 10353 LAURENCE V. EFNER, Primary Examiner.

ROBERT M. WALKER, Examiner. 

1. AN ELECTROMAGNETICALLY ACTUATED PUMP COMPRISING A HOUSING HAVING AN INLET AND AN OUTLET COAXIALLY ALIGNED THEREWITH, AN ENLARGED FLUID PASSAGEWAY BETWEEN SAID INLET AND SAID OUTLET, AN ARMATURE FORMED OF MAGNETIC MATERIAL POSITIONED IN THE FLUID PASSAGEWAY AND SPACED FROM THE PERIPHERAL WALLS THEREOF TO PROVIDE A PERIPHERAL CLEARANCE, PORT MEANS IN SAID ARMATURE COAXIALLY DISPOSED RELATIVE TO THE INLET AND THE OUTLET TO ACCOMMODATE FLUID FLOW PAST SAID ARMATURE, A FLEXIBLE IMPERFORATE SKIRT DISPOSED IN SAID PERIPHERAL CLEARANCE AND SEALING THE ARMATURE TO THE PERIPHERAL WALLS OF THE FLUID PASSAGEWAY, A FIRST ONE-WAY VALVE ON SAID ARMATURE TO PASS FLUID THROUGH SAID PORT MEANS OF SAID ARMATURE, A SECOND VALVE IN SAID HOUSING ARRANGED TO PASS FLUID ONLY IN THE SAME DIRECTION AS SAID FIRST VALVE, A SOLENOID IN SAID HOUSING DISPOSED BETWEEN SAID INLET AND OUTLET ADJACENT SAID ARMATURE, AND SPRING MEANS MOUNTING SAID ARMATURE FOR RECTILINEAR MOVEMENT ALONG THE AXIS OF SAID INLET AND OUTLET WITH THE PORT MEANS THEREOF IN COAXIAL ALIGNMENT WITH THE INLET AND OUTLET OF THE HOUSING, SAID SPRING MEANS BIASING SAID ARMATURE AWAY FROM SAID SOLENOID WHEREBY PULSED ENERGIZATION OF SAID SOLENOID CAUSES MOVEMENT OF SAID ARMATURE ASSEMBLY RECTILINEARLY RELATIVE TO THE AXIS OF SAID INLET AND OUTLET TO PUMP FLUID FROM SAID INLET TO SAID OUTLET. 